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Cytosine hypomethylation at CHG and CHH sites in the pleiotropic mutants of Mendelian inheritance in Catharanthus roseus

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Title Cytosine hypomethylation at CHG and CHH sites in the pleiotropic mutants of Mendelian inheritance in Catharanthus roseus
 
Creator Kumari, Renu
Yadav, Gitanjali
Sharma, Vishakha
Sharma, Vinay
Kumar, Sushil
 
Subject bisulphite sequencing
CMT3
DNA demethylases
DNA methyl transferases
demethylation
excision repair
mutagenic hot spots
phylogenetic relationships
5S rDNA
18S rDNA
RdDM
spontaneous mutagenesis
 
Description Accepted date: 22 July 2013
The 5S and 18S rDNA sequences of Catharanthus roseus cv 'Nirmal' (wild type) and its leafless inflorescence (lli), evergreen dwarf (egd) and irregular leaf lamina (ill) single mutants and lli egd, lli ill and egd ill double mutants were characterized. The lli, egd and ill mutants of Mendelian inheritance bore the names after their most conspicuous morphological feature(s). They had been chemically induced and isolated for their salt tolerance. The double mutants were isolated as morphological segregants from crosses between single mutants. The morphological features of the two parents accompanied salt tolerance in the double mutants. All the six mutants were hypomethylated at repeat sequences, upregulated and downregulated for many genes and carried pleiotropic alterations for several traits. Here the 5S and 18S rDNAs of C. roseus were found to be relatively low in cytosine content. Cytosines were preponderantly in CG context (53%) and almost all of them were methylated (97%). The cytosines in CHH and CHG (where H = A, T or C) contexts were largely demethylated (92%) in mutants. The demethylation was attributable to reduced expression of RDR2 and DRM2 led RNA dependant DNA methylation and CMT3 led maintenance methylation pathways. Mutants had gained some cytosines by substitution of C at T sites. These perhaps arose on account of errors in DNA replication, mediated by widespread cytosine demethylation at CHG and CHH sites. It was concluded that the regulation of cytosine ethylation mechanisms was disturbed in the mutants. ILL, EGD and LLI genes were identified as the positive regulators of other genes mediating the RdDM and CMT3 pathways, for establishment and maintenance of cytosine methylation in C. roseus.
Indian National Science Academy and Council of Scientific and
Industrial Research are thanked for grant of scientistship schemes to
SK, Department of Biotechnology is thanked for research grant for
work on periwinkle and for postgraduate fellowship to RK, Director of NIPGR is thanked for providing research facilities and SKA
Institution for Research, Education and Development is thanked for
grant of a postgraduate fellowship to VS.
 
Date 2015-11-06T10:11:01Z
2015-11-06T10:11:01Z
2013
 
Type Article
 
Identifier J. Genet., 92(3): 499-511
0022-1333
http://172.16.0.77:8080/jspui/handle/123456789/338
http://www.ias.ac.in/describe/article/jgen/092/03/0499-0511
 
Language en_US
 
Publisher Indian Academy of Sciences